Vaes Tolorro ("City of Bones" in Dothraki) is an abandoned city located in the Red Waste, north and west of Qarth. Like several other cities, Vaes Tolorro was once a thriving settlement that was then swallowed by the desert and later abandoned.
Daenerys Targaryen and her retinue stumble across the abandoned city whilst traversing the Red Waste. Though the city is abandoned, they still find viable wells and enough hardy-growing fruit to survive whilst Daenerys's bloodriders scout the surrounding area for succor. Upon learning of the relative proximity of Qarth, Daenerys's party moves on to that city, leaving Vaes Tolorrow abandoned once more.
Vaes Tolorro is located in the southern Red Waste, north-east of the similarly abandoned settlements of Vaes Orvik and Vaes Shirosi and north-west of Vaes Qosar. Qarkash, a satellite town of Qarth, is located on the Summer Sea due south. Qarth itself is located approximately 450 miles to the south-east.